As an addition to this post, a couple of images from a stop-off on the way down from St. Andrews a couple of weeks ago.
(Shame about the hotel, really. The little hill behind it is a nice spot to look at the bridge, but the building itself gets in the way.)
I'm often amazed by how beautiful a man-made structure can look. The Road Bridge, for example, is a simple, clean span of concrete - concrete! - yet I can just sit and look at it. Every month or so there's someone on the radio around here moaning about how wind-turbines are a horrendous offence to the beauty of the countryside, but I'm fascinated by them; again, I can just sit and stare at their gracefulness.
As for these two bridges, some day I really must make a conscious and deliberate effort to get some really great images, rather than a quick stop off the motorway on the way home...